Liver-to-lung microembolic NETs promote gasdermin D-dependent inflammatory lung injury in sickle cell disease.

Acute lung injury, referred to as the acute chest syndrome, is a major cause of morbidity and mortality in patients with sickle cell disease (SCD), which often occurs in the setting of a vaso-occlusive painful crisis. P-selectin antibody therapy reduces hospitalization of patients with SCD by ∼50%, suggesting that an unknown P-selectin-independent mechanism promotes remaining vaso-occlusive events. In patients with SCD, intraerythrocytic polymerization of mutant hemoglobin promotes ischemia-reperfusion injury and hemolysis, which leads to the development of sterile inflammation. Using intravital microscopy in transgenic, humanized mice with SCD and in vitro studies with blood from patients with SCD, we reveal for the first time that the sterile inflammatory milieu in SCD promotes caspase-4/11-dependent activation of neutrophil-gasdermin D (GSDMD), which triggers P-selectin-independent shedding of neutrophil extracellular traps (NETs) in the liver. Remarkably, these NETs travel intravascularly from liver to lung, where they promote neutrophil-platelet aggregation and the development of acute lung injury. This study introduces a novel paradigm that liver-to-lung embolic translocation of NETs promotes pulmonary vascular vaso-occlusion and identifies a new GSDMD-mediated, P-selectin-independent mechanism of lung injury in SCD.

Assessing the Feasibility of a Novel mHealth App in Hematopoietic Stem Cell Transplant Patients.

Hematopoietic stem cell transplantation (HCT) is a curative treatment option for patients with hematologic conditions but presents many complications that must be managed as a complex, chronic condition. Mobile health applications (mHealth apps) may permit tracking of symptoms in HCT. In seeking strategies to manage the complexities of HCT, our team collaborated with Sicklesoft, Inc., to develop an mHealth app specifically for HCT patients to allow for daily evaluation of patient health, Technology Recordings to better Understand Bone Marrow Transplantation (TRU-BMT). The primary value of this application is that of potentially enhancing the monitoring of symptoms and general health of patients undergoing HCT, with the ultimate goal of allowing earlier detection of adverse events, earlier intervention, and improving outcomes. To first evaluate patient interest in mHealth apps, we designed and administered an interest survey to patients at the 2017 BMT-InfoNet reunion. As a follow-up to the positive feedback received, we began testing the TRU-BMT app in a Phase 1 pilot study. Thirty patients were enrolled in this single-arm study and were given the TRU-BMT mHealth app on a smartphone device in addition to a wearable activity tracker. Patients were followed for up to 180 days, all the while receiving daily app monitoring. Adherence to TRU-BMT was approximately 30% daily and 44% weekly, and greater adherence was associated with increased meal completion, decreased heart rate, and shorter hospital stay. TRU-BMT assessments of symptom severity were significantly associated with duration of hospital stay and development of chronic graft-versus-host disease. Our findings suggest that using TRU-BMT throughout HCT is feasible for patients and established a proof-of-concept for a future randomized control trial of the TRU-BMT application in HCT. © 2021 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

User-Centered App Design for Acutely Ill Children and Adolescents.

Background and Objectives: The high level of acceptance and consistent use of smartphones by children and adolescents present new opportunities to monitor and collect health data. For acutely ill children and adolescents, collecting symptom data via smartphone applications (apps) provides patient-reported data that can be collected daily and offers the potential to provide a more comprehensive picture of the symptom experience. The purpose of this study was to employ user-centered design principles and medical professional input in order to obtain feedback and insight into redesigning our Technology Recordings for better Understanding Blood and Marrow Transplant (TRU-PBMT) app. This redesigned app will be used for children and adolescents with cancer or undergoing blood and marrow transplantation. Method: We interviewed six pediatric blood and marrow transplant patients (ages 10-17 years) who had pilot tested the app, and we surveyed 30 pediatric oncology clinicians. Results: Interview feedback from previous app users and survey feedback from clinicians guided the app redesign. We incorporated suggestions to make the app more engaging, meaningful, personal, and motivating in order to increase symptom reporting. We added emojis to the symptom tracker, a mood scale, and personalized symptom graphs. Conclusion: Leveraging mobile health technologies may be a useful and acceptable approach to obtain symptom data; however, design and software development needs to be evidenced-based and informed by user needs. Our approach using patient and clinician feedback was valuable in the redesign of the TRU-PBMT app and will contribute to symptom research for acutely ill children and adolescents.

Impaired Bile Secretion Promotes Hepatobiliary Injury in Sickle Cell Disease.

BACKGROUND AND AIMS: Hepatic crisis is an emergent complication affecting patients with sickle cell disease (SCD); however, the molecular mechanism of sickle cell hepatobiliary injury remains poorly understood. Using the knock-in humanized mouse model of SCD and SCD patient blood, we sought to mechanistically characterize SCD-associated hepato-pathophysiology applying our recently developed quantitative liver intravital imaging, RNA sequence analysis, and biochemical approaches. APPROACH AND RESULTS: SCD mice manifested sinusoidal ischemia, progressive hepatomegaly, liver injury, hyperbilirubinemia, and increased ductular reaction under basal conditions. Nuclear factor kappa B (NF-κB) activation in the liver of SCD mice inhibited farnesoid X receptor (FXR) signaling and its downstream targets, leading to loss of canalicular bile transport and altered bile acid pool. Intravital imaging revealed impaired bile secretion into the bile canaliculi, which was secondary to loss of canalicular bile transport and bile acid metabolism, leading to intrahepatic bile accumulation in SCD mouse liver. Blocking NF-κB activation rescued FXR signaling and partially ameliorated liver injury and sinusoidal ischemia in SCD mice. CONCLUSIONS: These findings identify that NF-κB/FXR-dependent impaired bile secretion promotes intrahepatic bile accumulation, which contributes to hepatobiliary injury of SCD. Improved understanding of these processes could potentially benefit the development of therapies to treat sickle cell hepatic crisis.

Platelet Extracellular Vesicles Drive Inflammasome-IL-1ß-Dependent Lung Injury in Sickle Cell Disease.

Rationale: Intraerythrocytic polymerization of Hb S promotes hemolysis and vasoocclusive events in the microvasculature of patients with sickle cell disease (SCD). Although platelet-neutrophil aggregate-dependent vasoocclusion is known to occur in the lung and contribute to acute chest syndrome, the etiological mechanisms that trigger acute chest syndrome are largely unknown.Objectives: To identify the innate immune mechanism that promotes platelet-neutrophil aggregate-dependent lung vasoocclusion and injury in SCD.Methods:In vivo imaging of the lung in transgenic humanized SCD mice and in vitro imaging of SCD patient blood flowing through a microfluidic system was performed. SCD mice were systemically challenged with nanogram quantities of LPS to trigger lung vasoocclusion.Measurements and Main Results: Platelet-inflammasome activation led to generation of IL-1ß and caspase-1-carrying platelet extracellular vesicles (EVs) that bind to neutrophils and promote platelet-neutrophil aggregation in lung arterioles of SCD mice in vivo and SCD human blood in microfluidics in vitro. The inflammasome activation, platelet EV generation, and platelet-neutrophil aggregation were enhanced by the presence of LPS at a nanogram dose in SCD but not control human blood. Inhibition of the inflammasome effector caspase-1 or IL-1ß pathway attenuated platelet EV generation, prevented platelet-neutrophil aggregation, and restored microvascular blood flow in lung arterioles of SCD mice in vivo and SCD human blood in microfluidics in vitro.Conclusions: These results are the first to identify that platelet-inflammasome-dependent shedding of IL-1ß and caspase-1-carrying platelet EVs promote lung vasoocclusion in SCD. The current findings also highlight the therapeutic potential of targeting the platelet-inflammasome-dependent innate immune pathway to prevent acute chest syndrome.

Use of Mobile Health Apps and Wearable Technology to Assess Changes and Predict Pain During Treatment of Acute Pain in Sickle Cell Disease: Feasibility Study.

BACKGROUND: Sickle cell disease (SCD) is an inherited red blood cell disorder affecting millions worldwide, and it results in many potential medical complications throughout the life course. The hallmark of SCD is pain. Many patients experience daily chronic pain as well as intermittent, unpredictable acute vaso-occlusive painful episodes called pain crises. These pain crises often require acute medical care through the day hospital or emergency department. Following presentation, a number of these patients are subsequently admitted with continued efforts of treatment focused on palliative pain control and hydration for management. Mitigating pain crises is challenging for both the patients and their providers, given the perceived unpredictability and subjective nature of pain. OBJECTIVE: The objective of this study was to show the feasibility of using objective, physiologic measurements obtained from a wearable device during an acute pain crisis to predict patient-reported pain scores (in an app and to nursing staff) using machine learning techniques. METHODS: For this feasibility study, we enrolled 27 adult patients presenting to the day hospital with acute pain. At the beginning of pain treatment, each participant was given a wearable device (Microsoft Band 2) that collected physiologic measurements. Pain scores from our mobile app, Technology Resources to Understand Pain Assessment in Patients with Pain, and those obtained by nursing staff were both used with wearable signals to complete time stamp matching and feature extraction and selection. Following this, we constructed regression and classification machine learning algorithms to build between-subject pain prediction models. RESULTS: Patients were monitored for an average of 3.79 (SD 2.23) hours, with an average of 5826 (SD 2667) objective data values per patient. As expected, we found that pain scores and heart rate decreased for most patients during the course of their stay. Using the wearable sensor data and pain scores, we were able to create a regression model to predict subjective pain scores with a root mean square error of 1.430 and correlation between observations and predictions of 0.706. Furthermore, we verified the hypothesis that the regression model outperformed the classification model by comparing the performances of the support vector machines (SVM) and the SVM for regression. CONCLUSIONS: The Microsoft Band 2 allowed easy collection of objective, physiologic markers during an acute pain crisis in adults with SCD. Features can be extracted from these data signals and matched with pain scores. Machine learning models can then use these features to feasibly predict patient pain scores.

Customization of the TRU-PBMT App (Technology Recordings to better Understand Pediatric Blood and Marrow Transplant).

PURPOSE: Our investigative team is integrating mobile health technologies into pediatric blood and marrow transplant (PBMT) care. We aim to evaluate whether patient-generated health data can be used to monitor health status and enhance symptom management. While there are numerous health-related apps, none address the symptoms or care needs specific to PBMT patients. This article describes development of the Technology Recording to better Understand Pediatric Blood and Marrow Transplant (TRU-PBMT) mobile application. DESIGN AND METHODS: A one-time survey was distributed to PBMT clinicians, caregivers, and outpatients to elicit feedback and suggestions for the app's design. RESULTS: Feedback from clinicians (n = 23), caregivers (n = 5), and PBMT outpatients (n = 4) indicated the app would be acceptable and useable with this group of patients between eight and eighteen years of age. Suggestions from respondents included: making the app language and graphics more child-friendly; adding symptoms such as fatigue, mucositis, bleeding; and a visual stool chart. CONCLUSION: Patient, caregiver, and clinician feedback was valuable in creation of the TRU-PBMT app. We designed a pediatric friendly, PBMT-symptom-specific app, which we will test in future studies. IMPLICATIONS FOR PRACTICE: This app facilitates patient-generated health data collection and informs health care plans.

Abstract Animations for the Communication and Assessment of Pain in Adults: Cross-Sectional Feasibility Study.

BACKGROUND: Pain is the most common physical symptom requiring medical care, yet the current methods for assessing pain are sorely inadequate. Pain assessment tools can be either too simplistic or take too long to complete to be useful for point-of-care diagnosis and treatment. OBJECTIVE: The aim was to develop and test Painimation, a novel tool that uses graphic visualizations and animations instead of words or numeric scales to assess pain quality, intensity, and course. This study examines the utility of abstract animations as a measure of pain. METHODS: Painimation was evaluated in a chronic pain medicine clinic. Eligible patients were receiving treatment for pain and reported pain more days than not for at least 3 months. Using a tablet computer, participating patients completed the Painimation instrument, the McGill Pain Questionnaire (MPQ), and the PainDETECT questionnaire for neuropathic symptoms. RESULTS: Participants (N=170) completed Painimation and indicated it was useful for describing their pain (mean 4.1, SE 0.1 out of 5 on a usefulness scale), and 130 of 162 participants (80.2%) agreed or strongly agreed that they would use Painimation to communicate with their providers. Animations selected corresponded with pain adjectives endorsed on the MPQ. Further, selection of the electrifying animation was associated with self-reported neuropathic pain (r=.16, P=.03), similar to the association between neuropathic pain and PainDETECT (r=.17, P=.03). Painimation was associated with PainDETECT (r=.35, P<.001). CONCLUSIONS: Using animations may be a faster and more patient-centered method for assessing pain and is not limited by age, literacy level, or language; however, more data are needed to assess the validity of this approach. To establish the validity of using abstract animations ("painimations") for communicating and assessing pain, apps and other digital tools using painimations will need to be tested longitudinally across a larger pain population and also within specific, more homogenous pain conditions.

Mobile health intervention for youth with sickle cell disease: Impact on adherence, disease knowledge, and quality of life.

BACKGROUND: Adherence to illness self-management among youth with sickle cell disease (SCD) positively impacts health outcomes and decreases overall healthcare costs. Despite this, children with SCD face several barriers to adherence, with adherence rates that remain moderate to low. The current feasibility study examined the Intensive Training Program (ITP), a mobile health (mHealth) intervention for youth with SCD designed to promote disease knowledge, adherence, and patient-provider communication. PROCEDURE: Youth with SCD prescribed hydroxyurea between ages 7-18 completed baseline disease knowledge and psychosocial assessments and then were provided with the ITP app. Youth participated in the 90-day ITP, during which they completed three education modules, tracked adherence through daily self-recorded videos on the app, and received video messages from providers. Participants completed poststudy knowledge, psychosocial, and feasibility questionnaires. Medication possession ratio (MPR) was obtained via pharmacy-refill rates. RESULTS: Thirty-two youths (mean age = 13.0 years) participated, with an average adherence tracking rate of 0.6 (standard deviation = 0.34). All participants demonstrated increased MPR (0.57-0.74, P < 0.001, d = 0.75) and disease knowledge (59.6-88.6%, P < 0.001). There was variable engagement in the ITP; completers demonstrated significantly better SCD-related functioning (P < 0.05), higher parent-reported treatment functioning (P < 0.05), and lower pain impact than noncompleters of the ITP (P < 0.05). CONCLUSIONS: Results support the ITP can feasibly be implemented to promote adherence among youth with SCD. All participants demonstrated increased adherence and disease knowledge. However, there was variable engagement and only intervention completers showed improvements in psychosocial outcomes. Further research is needed to evaluate long-term outcomes and ways to promote engagement in mHealth interventions among the youth.

Utilizing a Novel Mobile Health "Selfie" Application to Improve Compliance to Iron Chelation in Pediatric Patients Receiving Chronic Transfusions.

Iron chelation therapy can prevent iron overload for pediatric patients with sickle cell disease and ß-thalassemia major; however, adherence is suboptimal. Therefore, we developed an intensive training program (ITP), to improve medication management and disease knowledge. The objectives were to determine feasibility of the ITP and its preliminary impact on adherence, disease knowledge, and health outcomes. Pediatric patients were recruited to participate in the ITP over a 90-day period and were followed for 6 months. The ITP consisted of 3 components: (1) provider-led education modules; (2) patient recording daily videos of at-home medication administration; and (3) provider feedback through video messages through the ITP app. Eleven patients participated (mean=12.4 y). Initially, patients endorsed high satisfaction and ease of use and tracked their medication usage 81% (24 out of 30) of days. At 90 days, adherence rates remained consistent (80%) and disease knowledge retention was high (96%). At 6 months, participants exhibited a clinically relevant decrease in serum ferritin, which trended toward statistical significance (P=0.068). Medication possession ratio did not significantly increase (0.65 to 0.72; not significant). The mobile ITP was feasibly implemented in a clinical setting; in addition, high levels of compliance, disease knowledge retention, and acceptance encourage larger studies evaluating mobile health technology to improve child health parameters.

Lung vaso-occlusion in sickle cell disease mediated by arteriolar neutrophil-platelet microemboli.

In patients with sickle cell disease (SCD), the polymerization of intraerythrocytic hemoglobin S promotes downstream vaso-occlusive events in the microvasculature. While vaso-occlusion is known to occur in the lung, often in the context of systemic vaso-occlusive crisis and the acute chest syndrome, the pathophysiological mechanisms that incite lung injury are unknown. We used intravital microscopy of the lung in transgenic humanized SCD mice to monitor acute vaso-occlusive events following an acute dose of systemic lipopolysaccharide sufficient to trigger events in SCD but not control mice. We observed cellular microembolism of precapillary pulmonary arteriolar bottlenecks by neutrophil-platelet aggregates. Blood from SCD patients was next studied under flow in an in vitro microfluidic system. Similar to the pulmonary circulation, circulating platelets nucleated around arrested neutrophils, translating to a greater number and duration of neutrophil-platelet interactions compared with normal human blood. Inhibition of platelet P-selectin with function-blocking antibody attenuated the neutrophil-platelet interactions in SCD patient blood in vitro and resolved pulmonary arteriole microembolism in SCD mice in vivo. These results establish the relevance of neutrophil-platelet aggregate formation in lung arterioles in promoting lung vaso-occlusion in SCD and highlight the therapeutic potential of targeting platelet adhesion molecules to prevent acute chest syndrome.

Attitudes of Primary Care Physicians Toward Sickle Cell Disease Care, Guidelines, and Comanaging Hydroxyurea With a Specialist.

BACKGROUND: Sickle cell disease (SCD) is a complex chronic disease requiring multidisciplinary care that involves primary care physicians (PCPs) working with a hematologist or SCD specialists. However, PCPs often lack access to SCD specialists and are unaware of SCD guidelines or efficacious treatment. METHODS: We partnered with Community Care of North Carolina (CCNC) to identify assigned PCPs for SCD patients with Medicaid across North Carolina. CCNC network administrators distributed a web-based questionnaire for completion. The questionnaire involved 12 self-reported items on a yes-no or a 1 to 5 Likert-type scale that assessed PCP attitudes toward SCD care, awareness of recent guidelines, and comanaging hydroxyurea. RESULTS: Of the 53 PCPs who completed the electronic survey, 73% felt they were comfortable with the number of SCD patients in their practice. Most PCPs reported having infrequent communications with an SCD specialist (67%) and most were also not aware of the 2014 SCD guidelines (66%). Many reported that they would frequently use the new SCD guidelines if provided to them (76%). Furthermore, 51% of PCPs expressed comfort with using mobile apps to access SCD guidelines and provided email contact to receive further information. The majority also reported being comfortable comanaging hydroxyurea with an SCD specialist (65%). CONCLUSION: Few PCPs in North Carolina were aware of the new SCD guidelines or had regular communication with an SCD specialist. The majority of PCPs, however, demonstrated a favorable attitude toward receiving the SCD guidelines and comanaging hydroxyurea with a specialist. In response to this gap in care, we have developed a mobile-based SCD toolbox specifically for PCPs to provide guidelines, algorithms, and a method to communicate with local SCD specialists. With the interest in receiving these guidelines, we are confident the toolbox will provide an easy to use platform to assist PCPs to utilize the SCD guidelines.

Phase 1 Study of a Sulforaphane-Containing Broccoli Sprout Homogenate for Sickle Cell Disease.

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy worldwide. Our previous results indicate that the reduced oxidative stress capacity of sickle erythrocytes may be caused by decreased expression of NRF2 (Nuclear factor (erythroid-derived 2)-like 2), an oxidative stress regulator. We found that activation of NRF2 with sulforaphane (SFN) in erythroid progenitors significantly increased the expression of NRF2 targets HMOX1, NQO1, and HBG1 (subunit of fetal hemoglobin) in a dose-dependent manner. Therefore, we hypothesized that NRF2 activation with SFN may offer therapeutic benefits for SCD patients by restoring oxidative capacity and increasing fetal hemoglobin concentration. To test this hypothesis, we performed a Phase 1, open-label, dose-escalation study of SFN, contained in a broccoli sprout homogenate (BSH) that naturally contains SFN, in adults with SCD. The primary and secondary study endpoints were safety and physiological response to NRF2 activation, respectively. We found that BSH was well tolerated, and the few adverse events that occurred during the trial were not likely related to BSH consumption. We observed an increase in the mean relative whole blood mRNA levels for the NRF2 target HMOX1 (p = 0.02) on the last day of BSH treatment, compared to pre-treatment. We also observed a trend toward increased mean relative mRNA levels of the NRF2 target HBG1 (p = 0.10) from baseline to end of treatment, but without significant changes in HbF protein. We conclude that BSH, in the provided doses, is safe in stable SCD patients and may induce changes in gene expression levels. We therefore propose investigation of more potent NRF2 inducers, which may elicit more robust physiological changes and offer clinical benefits to SCD patients. Trial registration: ClinicalTrials.gov NCT01715480.

Usability and Feasibility of an mHealth Intervention for Monitoring and Managing Pain Symptoms in Sickle Cell Disease: The Sickle Cell Disease Mobile Application to Record Symptoms via Technology (SMART).

Patients with sickle cell disease frequently experience severe pain events that lead to unplanned healthcare utilization. Mobile health tools (mHealth) may help prevent these events by providing remote monitoring and self-management support. This article describes the feasibility of the Sickle cell disease Mobile Application to Record symptoms via Technology (SMART), an mHealth app developed to help sickle cell disease patients monitor and manage their day-to-day symptoms. Fifteen patients recorded their pain intensity using a paper visual analog scale (VAS) and then repeated this measurement using an electronic VAS pain measure on SMART. Patients continued using SMART to record clinical symptoms, pain intensity, location and perceived severity, and treatment strategies for at least 28 days. Patient median age was 29 years (range 16-54); 60.0% were male. There was a high intraclass correlation between pain measurements entered on the paper VAS and SMART on the iPhone and the iPad We found a strong association between patient perceived pain severity and pain intensity entries using SMART (b = 1.71; p < 0.01). Daily compliance with SMART entries was a mean 75.0%, with a high of 85.7% in week 1 and low of 57.9% in week 4; however, one-third (n = 5) of the patients were 100.0% compliant even in week 4. Patients who were over age 35 or used an iPad for the study had the highest compliance rates. This study showed that SMART is a useable and feasible method for monitoring daily pain symptoms among adolescents and adults with sickle cell disease-related pain.

Patients welcome the Sickle Cell Disease Mobile Application to Record Symptoms via Technology (SMART).

The widespread use of mobile phones among patients provides a unique opportunity for the development of mobile health intervention designed specifically for sickle cell disease, which will improve self-management as well as health care delivery. Our objective was to determine the receptiveness of patients with sickle cell disease to technology and a mobile application (app) designed for sickle cell disease. Phase I included 100 patients who completed a survey inquiring about receptiveness to technology and use of mobile devices to self-manage and communicate with providers. Phase II surveyed 17 additional patients who tested a newly developed sickle cell disease app, to report its usability and utility. In Phase I, on a 0-10 Likert scale where 0 is not comfortable, and 10 is extremely comfortable, 87.0% of participants reported >5 comfort level using a mobile device for health care management. Participants were comfortable with texting (81.0%) and emailing (77.0%) but not with social media (40.0%). Most participants (84.0%) owned computer devices (desktops, laptops, tablets, or iPads), and 92.0% owned mobile devices. In Phase II, participants reported that the app tested was useful to track pain (88.0%), and 94.0% reported that it was easy to use, practical, and useful for health self-management. All reported that the app was useful to help one communicate with providers. Following the use of our app, patients found it an extremely valuable tool for tracking pain, health management, and communicating with providers. We conclude that mobile technology might provide an appropriate venue for sickle cell disease healthcare management.

Factors associated with survival in a contemporary adult sickle cell disease cohort.

In this study, the relationship of clinical differences among patients with sickle cell disease (SCD) was examined to understand the major contributors to early mortality in a contemporary cohort. Survival data were obtained for 542 adult subjects who were enrolled since 2002 at three university hospitals in the southeast United States. Subjects were followed up for a median of 9.3 years. At enrollment, clinical parameters were collected, including hemoglobin (Hb) genotype, baseline laboratory values, comorbidities, and medication usage. Levels of soluble adhesion molecules were measured for a subset of 87 subjects. The relationship of clinical characteristics to survival was determined using regression analysis. Median age at enrollment was 32 years. Median survival was 61 years for all subjects. Median survival for Hb SS and Sß(0) was 58 years and for Hb SC and Sß(+) was 66 years. Elevated white blood count, lower estimated glomerular filtration rate, proteinuria, frequency of pain crises, pulmonary hypertension, cerebrovascular events, seizures, stroke, sVCAM-1, and short-acting narcotics use were significantly associated with decreased survival. Forty-two percent of subjects were on hydroxyurea therapy, which was not associated with survival. SCD continues to reduce life expectancy for affected individuals, particularly those with Hb Sß(0) and SS. Not only were comorbidities individually associated with decreased survival but also an additive effect was observed, thus, those with a greater number of negative endpoints had worse survival (P < 0.0001). The association of higher sVCAM-1 levels with decreased survival suggests that targeted therapies to reduce endothelial damage and inflammation may also be beneficial.

Effect of propranolol as antiadhesive therapy in sickle cell disease.

Sickle red blood cells (SSRBCs) adhere to both endothelial cells (ECs) and the extracellular matrix. Epinephrine elevates cyclic adenosine monophosphate in SSRBCs and increases adhesion of SSRBCs to ECs in a ß-adrenergic receptor and protein kinase A-dependent manner. Studies in vitro as well as in vivo have suggested that adrenergic stimuli like epinephrine may contribute to vaso-occlusion associated with physiologic stress. We conducted both animal studies and a Phase I dose-escalation study in sickle cell disease (SCD) patients to investigate whether systemically administered propranolol inhibits SSRBC adhesion and to document the safety of propranolol in SCD. Systemically administered propranolol prevented SSRBC adhesion and associated vaso-occlusion in a mouse model. In patients receiving a single oral dose of 10, 20, or 40 mg propranolol, SSRBC adhesion to ECs was studied before and after propranolol, with and without stimulation with epinephrine. Propranolol administration significantly reduced epinephrine-stimulated SSRBC adhesion in a dose dependent manner (p = 0.03), with maximum inhibition achieved at 40 mg. Adverse events were not severe, did not show dose dependence, and were likely unrelated to drug. No significant heart rate changes occurred. These results imply that ß-blockers may have a role as antiadhesive therapy for SCD.

MYH9 and APOL1 are both associated with sickle cell disease nephropathy.

Renal failure occurs in 5-18% of sickle cell disease (SCD) patients and is associated with early mortality. At-risk SCD patients cannot be identified prior to the appearance of proteinuria and the pathobiology is not well understood. The myosin, heavy chain 9, non-muscle (MYH9) and apolipoprotein L1 (APOL1) genes have been associated with risk for focal segmental glomerulosclerosis and end-stage renal disease in African Americans. We genotyped 26 single nucleotide polymorphisms (SNPs) in MYH9 and 2 SNPs in APOL1 (representing the G1 and G2 tags) in 521 unrelated adult (18-83 years) SCD patients screened for proteinuria. Using logistic regression, SNPs were evaluated for association with proteinuria. Seven SNPs in MYH9 and one in APOL1 remained significantly associated with proteinuria after multiple testing correction (P < 0·0025). An MYH9 risk haplotype (P = 0·001) and the APOL1 G1/G2 recessive model (P < 0·0001) were strongly associated with proteinuria, even when accounting for the other. Glomerular filtration rate was negatively correlated with proteinuria (P < 0·0001), and was significantly predicted by an interaction between MYH9 and APOL1 in age-adjusted analyses. Our data provide insight into the pathobiology of renal dysfunction in SCD, suggesting that MYH9 and APOL1 are both associated with risk.

Living with sickle cell disease: traversing 'race' and identity.

OBJECTIVES: Sickle cell disease (SCD) has a distinctive social history that continues to influence research and clinical practice related to the disease. Despite the historical link between SCD and concepts of 'race', there is limited empirical information on the relationships among SCD patients' 'race'/ancestry/ethnicity/nationality, their beliefs and attitudes associated with these identities, and their SCD experiences and outcomes. We conducted a preliminary study to explore some of these relationships. DESIGN: This US-based study comprised 46 adults with SCD, 20 males and 26 females, with an average age of 32.04 (18-59) years. Using US Census 'race' categories, 42 participants identified themselves as 'Black or African American', two as 'Hispanic/Latino', and two as 'Other'. All participants completed a computer-based questionnaire that included measures of sociodemographics and 'racial' identity. Indicators of disease severity and frequency of hospitalizations were obtained from their medical records. Two open-ended questions explored the impact of SCD and 'race' on participants' experiences and another probed their understanding of the term 'race'. RESULTS: Overall, participants had positive regard for their 'race' and endorsed assimilation and humanist ideologies. 'Racial' identity was not related to disease severity or hospitalizations. Participants with non-US-born parents had higher levels of minority ideology than those with US-born parents (p<.01). Public regard beliefs were negatively associated with participants' perspective that SCD influenced how others perceived and treated them (r=-.35; p=.02). Centrality of 'race' and a nationalist ideology were positively associated with participants' belief that their 'race' influenced their experience with SCD (r=.31; p=.04 and r=.45; p=.001, respectively). The open-ended responses reveal that SCD and 'race' had varied effects on participants' experiences. CONCLUSION: This study illustrates the complexity of the interplay between 'racial' identity beliefs and patients' experiences with SCD, as well as the role of 'race' in these experiences. Implications of the findings are discussed.